Azomethines



Patented Feb. 12, 1946 UNITED STATES PATENT orrlcs AZOMETHINES NoDrawing. Application January 26, 1944,

Serial No. 519,794

- .8 Claims.

This invention relates to azomethines of the general formula:

wherein R and R are hydrocarbon groups, X is an organic radical derivedfrom a primary amine, and n is an integer from one to two, inclusive.

The azomethines of this invention are derived from primary amines andcyanoethylated aldehydes of the formula:

wherein R1 and R2 are hydrocarbon groups. The 7 reaction of such analdehyde and a primary amine is readily effected from room temperatureup to about 150 C. or more. The reaction may be effected by directmixing of the components, preferably, but not necessarily, in equivalentamounts. If desired, a solvent may be used, such as water,

alcohol, benzene, or toluene, and the reaction used may be obtained bythe methods described in United States applications Serial No. 466,050,now issued as United States Patent No. 2,353,687, and acontinuation-in-part thereof, Serial No. 488,400, filed May 25, 1943,now issued as United In the first of these specifications, aldehydeshaving two hydrocarbon substituents and one hydrogen atom on the carbonatom in alpha position to the CH0 group are shown to react in thepresence of an alkaline catalyst with acrylonitrile 'group such asbutenyl-2 or the like.

position to the CH0 group. It will be evident that fl-cyanoethylatedaldehydes made by other methods are also operative as long as they areof the type:

' HlCH|CN R is generally an alkyl group, such as methyl, ethyl, propyl,isopropyl, butyl, isobutyl, octyl, or the like. R. may be an alkylgroup, such as methyl, ethyl, propyl, isopropyl,butyl,-isobutyl, amyl,hexyl, octyl, or the like,.or an alkenyl group,

particularlyone havingan ethnoidgroup joined to the central carbon atomto which R. is attached, such as R"CH=CH-, wherein R" is alkyl, such asmethyl, ethyl, butyl, octyl, etc., or aralkyl, such as benzyl,butylbenzyl, phenyl ethyl, phenoxyethyl, or the like, or aryl, such asphenyl, methylphenyl, tert.-butyl phenyl, etc., or cycloalkyl, such ascyclohexyl, or methyl-cyclohexyl. R may also be an unsaturatedhydrocarbon Any aldehyde having a p-cyanoethyl group and two hydrocarbonsubstituents on the carbon atom alpha to the carbonyl group appearsoperative.

For reaction with the above aldehydes, there may be used a primary aminefrom the aliphatic, cycloaliphatic, arylaliphatic, aromatic, orheterocy-clic series. The primary amine may be saturated or unsaturated.It may have in the preferred forms a residue, X, monovalent or bivalent,consisting of carbon and hydrogen. or it may conta n in the organicresidue substituents such as States Patent No. 2,370,006.

nitro, sulfonyl, alkoxy, aryloxy, hydroxy, imino, carbalkoxy, or othergroups, including halogen groups. Typical primary amines aremethylamine,ethylamine, butylamine, amylamine, dodecylamine, octadecylamine, and.homologues thereof, allylamine methallylamine, octadecenylamine,ethanolamine, ethylene diamine, diethylene triamine, triethylenetetramine, butoxyethylamine, diaminodiethyl ether, cyclohexylamine,aniline and the various nuclear chloro,

I br0mo, 'nitr0, methoxy, acetyl, or hydroxy nuclearly substitutedanilines, naphthylamines and the various nuclearly substitutedderivatives thereof, benzylamine, tetrahydrofurfurylamlne, and manyother primary amines.

The new'azometmnes which are formed by reaction of the above aldehydesand primary amines are valuable intermediates for the preparation ofpharmaceuticals, insecticides, and plastics. The nitrile group may bereduced to an amine group ethyl-diethylacetaldehyde (26 grams) washeated for two hours at 95-100 0., dried and distilled in yacuo. Theproduct having the formula:

or hydrolyzed to form amides, acids, salts, and 5 Z' esters. 'Theazomethine group may be hydrogen- 'Q ated to yield a secondary aminegroup or may be 111: otherwise altered by nown reactions. Forindistilled over stance, the new azomethines readily add HCN to yellowoil. 170 180 C/2-3 m as a pale form new adipic nitriles disubstituted inaposi- Example 5 tion beta to the added nitrile group.

The following examples are illustrative of the one molecular equivalenteach of n'butylame preparation of the azomethines of this invention. andz'ethyl'z'm'cyanoethyl) were heated for one hour at 100 C. and thereaction Emmpl 1 product distilled invacuo. The product having A mixtureof 88.5 gramsof aqueous 35% meththe formula: v gaming solution and 86'grams of p-cyanoethyl- 0,11.

ethylace aldehyde was stirred at room temperature for three hours andthen heated under a NCcgcm & cn-Ncmcmcmcm reflux condenser at 40-45 C.for two and one- H quarter hours. After standing overnight, the anmixture was washed. the oil layer dried and dis- 5 tilled in vacuo. Thebase having the formula:

02H: o gilstilled at 130 433 0/1 mm. as a pale yellow 2H5 In a similarmanner, the following products distilled over at 92-93 C./2 mm. as acolorless were Obtained by heating reacting Proportions on m a of gramsof aldehydes amines indicated in Example 2 table below. The reactionwith methylamine was carried out at 30 to 65 C., while the other Amixture of 36.2 grams of -2-cyanoethyl-2- reactions were eflected atsteam bath temperaethylhexaldehyde and 11.4 grams of allylamine tures of90-100 C. was heated one hour on a steam bath. The prod- B uct was thendried in vacuo at 90 C. and finally distilled under reduced pressure.The product NGCHCH'ALC-HO 9mm having the formula:

01H] 3 NocmcHrd-cn-N-cHr-cn-cm 40 I NCCHsCHg-C-CH-N-X B mine 323553 6?EthyL. n-Butyl Methylamine a 1o9-mr2 mm. 130.... "1 n-Bllty nminn 11-33137/1 mm. Do.. 8 235-244/2 mm. Do.. 1 l40-l45/l mm 100.. 1 235-24l/2mm. Do.- 1 240-245/2 mm. Do 2 l-185/l mm. 130.. 3 99-202/2 mm. Do..-- do1 l l87l3 mm. 90.--- omcmcn=on All amine 1 -1ao/1 mm.

distilled over at 132-133 C./2.5 mm. as a pale 55 yellow oil in a yieldof 30 grams.

Example 3 Example 4 A mixture of aniline (15.8 grams) and p-cyano- Weclaim: 1. An azomethine of the formula:

R [NCCH|CH|(:J-CH- wherein R and R e are aliphatic hydrocarbon groups, Xis a hydrocarbon radical, and ,n. is an integer having a value of one totwo, inclusive.

2. An azomethine of the formula:

1 R NccrncH o-cn-Nx wherein R and R are aliphatic hydrocarbon groups andX is a monovalent hydrocarbon radical. l

3. An azomethine of the formula:

- R NC CHsCHr-(S-CH-NX wherein R and R are alkyl groups and 31s a.monovalent hydrocarbon radical.

4. An azomethine of the formula:

R NC cmcm-b-cn-ncm wherein R and R are alkyl groups.

5. An azomethine of the formula:

R @TCCHaCHg--CH NX wherein R is an alkyl group and R is a hydrocarbongroup containing an ethnoid group joined to the carbon atom to which thegroup R. is attached and X is a monovalent hydrocarbon group.

6. A compound of the. formula:

HERMAN A. BRUSON. THOMAS W. RIENER.

